These are the signature recipe from the first Sneaky Chef book. Everyone was amazed that no one — neither kids nor adults — could detect the hidden spinach, blueberries, oat bran, or the missing fat and sugar.
Preheat the oven to 350 degrees.
Spray only the bottom with the nonstick cooking spray, not the sides, of an 8-by-8-inch or 9-by-9-inch baking pan.
Melt the butter and chocolate chips together in a double boiler or metal bowl over simmering water (or in a microwave, checking every 15 seconds). Remove from heat and allow mixture to cool a bit. Meanwhile, in another bowl, stir together the eggs, vanilla, sugar, and Purple Purée. Combine this purple egg mixture with the cooled chocolate mixture.
In a mixing bowl, stir together the flours, cocoa powder, oats, and salt. Add this to the chocolate mixture and blend thoroughly; pour the entire mixture into the baking pan.
Bake for 30-35 minutes, until a toothpick comes out clean. Allow to cool completely in pan before cutting the brownies and use a plastic or butter knife. Dust with powdered sugar, if desired. Keeps for a week in the refrigerator, covered tightly.